In the related art, a cutting tool made of diamond-coated cemented carbide (hereinafter, referred to as “diamond-coated tool”) in which a cutting tool body made of WC-based cemented carbide (hereinafter, referred to as “cemented carbide”) is coated with a diamond film is known. In order to improve the adhesion between the cutting tool body and the diamond film, various proposals have been made such as forming a diamond film on the cutting tool body.
For example, Japanese Unexamined Patent Application, First Publication No. H11-193479 discloses a cutting tool obtained by coating the surface of a cemented carbide body having concave and convex with a diamond film through an intermediate layer that prevents diffusion of the component of the cemented carbide body.
Furthermore, Japanese Unexamined Patent Application, First Publication No. 2002-79406 discloses that a diamond film is laminated to cause the crystal grain size of the surface to be 2 μm or less in order to perform machining with high surface machining accuracy.